Four clear transparent glasses of varying sizes are shown. Each glass is approximately twice as large as the previous one.

You fill the smallest glass with some milk. When the contents of the smallest glass are poured into the next bigger glass that is twice as big as the smallest one, it is found to have filled up. The milk has magically doubled itself. You are able to double the milk twice more. Absolutely astounding!!

You could also do this routine in the reverse, where you start with the biggest glass and keep diminishing the milk till it fits into the smallest glass. Either way when done with some patter, this effect is simply mind blowing!!

Four clear glasses are provided with this trick; the biggest glass being 5.5" tall and the smallest glass being just over 2.25" tall.